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A215765
Number of undirected labeled graphs on n nodes with exactly 5 cycle graphs as connected components.
2
1, 15, 140, 1190, 10857, 109935, 1222210, 14771955, 192855949, 2705536834, 40597839100, 648954464340, 11010645610113, 197646020548569, 3742573587799761, 74560940574685875, 1559079985774886316, 34142131775027937276, 781462189858194371736
OFFSET
5,2
LINKS
MAPLE
T:= proc(n, k) option remember; `if`(k<0 or k>n, 0, `if`(n=0, 1,
add(binomial(n-1, i)*T(n-1-i, k-1)*ceil(i!/2), i=0..n-k)))
end:
a:= n-> T(n, 5):
seq (a(n), n=5..25);
CROSSREFS
Column k=5 of A215771.
Sequence in context: A327506 A346955 A346920 * A055903 A320818 A026859
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 23 2012
STATUS
approved